Railway-traffic-controlling apparatus



- Dec. 15, 1925- 5 C. H. ZIERDT RAILWAY TRAFFIC CONTROLLING APPARATUS Filed April 2, 1924 INVENTOR Patented Dec. 15, 1925.

UNITED. STATES PATENT OFFlCE.

CONRAD H. ZIERDT, OF ROSEDALE, PENN TOWNSHIP, ALLEGHENY COUNTY, PENN- SYLVANIA, ASSIGNOR TO THE UNIQN SJVITCI-I & SIGNAL COMPANY, OF SWISS- VALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-UON'IROLLING APPARATUS.

Application filed April 2,

To all whom it may concern:

Be it known that I, CONRAD H. Zinnn'r, a citizen of the United States, residing at Rosedale, Penn Township, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway-Traffic-Controlling Apparatus, of which the following is a specification.

My invention relates to railway traffic controlling apparatus, and particularly to apparatus of the type comprising means responsive to currents flowing in the trackway for controlling trafiie. More particularly my present invention relates to the trac way portion of such apparatus.

I will describe two forms of railway traffic controlling apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form and arrangement of trackway circuit embodying my invention. Fig.2 18 a view showing a modification of the apparatus illustrated in Fig. 1 and also embodying my invention.

Similar reference characters refer to similar parts in both views.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track ra ls of a stretch of' railway track. These rails are divided, by means of insulated yomts 2, into a plurality of successive sections, of which two adjoining sections A-B and BC are here shown.

Each section is provided with a track transformer designated by the reference character T with a suitable exponent and having its secondary winding 3 connected across the rails adjacent the left hand end of the section. An impedance 5 is interposed between the secondary 3 of each track transformer T and one rail 1 of the associated section in the usual manner. The primary winding 4 of each track transformer is constantly supplied with alternating current from a source not shown in the drawing.

Each section is also provided with a transformer which I will term a protecting? transformer and which is designated by the reference character with a suitable exponent. The primary 7 of each pro 1924. Serial No. 203,681.

tecting transformer D is constantly connected across the rails adjacent the right hand end of the corresponding section.

Each section is further provided with a track relay designated by the reference character R with a distinguishing exponent, which relay is connected with the secondary 8 of the protecting transformer for the same section.

The track relays B may be used to control suitable apparatus, not shown in the drawing, in any desired manner.

Means are also provided for supplying the rails of each. section. in parallel with a cur rent which I shall hereinafter term a loop current. For this purpose I provide an impedanoe 6 connected across the rails adja cent the left hand end of each section. The immediate supply of loop current to each section is a loop transformer local to such section and here designated by the reference character J with a suitable distinguished exponent. The primary 9 of each such loop transformer is supplied with alternating current from some suitable source not shown in the drawing. Referring particularly to transformer J", the left hand terminal of the secondary 10 of this transformer is con nected with the mid point of impedance 6 in section AB, and the right hand terminal of this secondary is connected with the mid point a of primary 7 of transformer D. A resistance 30 is interposed between the secondary 10 of transformer J" and the primary transformer D one function of which is to regulate the amount of current flowing through the loop circuit. It will thus be clear that each section is provided with a loop circuit including the secondary 10 of a loop transformer, the oppositely connected halves of the associated impedance 6 in parallel, the rails 1 and 1 of the associated. section in parallel, a resistance 30 and the two halves of the primary 7 of a protecting transformer D. It will be observed however, that loop current flows in opposite directions through the two halves o the primary of the protecting transformer D and hence has no effect upon the track relay R associated therewith.

If, however, a break occurs in one rail of a section, all the loop current will flow through one half of the primary of the protecting transformer. For example I will assume that a break occurs in rail 1 of sec tion A E. All the loop current will then low through the right hand half of primary 7 of transformer D. The impedance offered to loop current by this winding is a comparatively small part of the total impedance of the loop circuit, and the trans former 1) acts as a current transformer to loop current. The ratio of transformer 3 for this unbalanced loop current is however only one half of the ratio oi this transformer for track circuit current since only half the turns ol the primary T are then included in the loop circuit. The current flowing through relay R" due to the loop nt in primary 7 will therefore be only a traction of the total loop current in windand the parts are so proportioned that it will not be picked up or held in its energized condition by a current of this reduced value. shown in the drawing the transihnmcr D has the same number of turns in primary '4' as in secondary 8, but this pzu'ticular construction is not essential.

The track currents may be used to control tra'liic governing means in any desired manner.

Referring now to Fig. 2, the single section A B here shown is connected with adjacent sections by impedance bonds designated by the reference character I; with suitable distinguishing exponents. Each impedance bond K is of the usual form comprising two impedances l2 and 13 connected across the rails of the adjoining sections, the mid points of such impedances being connected together by means of a conductor 1st. These impedance bonds serve to conduct propulsion current past the insulated joints 2 in the usual and well known manner.

The track circuit for section A-B in Fig. 2 is the same as in Fig. 1, and the loop circuit also the same as in Fig. 1, except that the left hand terminal of secondary 10 of transformer J is connected with the conductor of impedance bond K. The operation of the apparatus shown in Fig. 2 is the same as that of the apparatus shown in 1 and will be readily understood without further explanation.

One advantage of my invention is that the track relay can not be picked up or held in its energized condition by loop current as a result of a broken rail.

Although I have herein shown and described only two forms of trackway apparatus embodying my invention, it is un derstood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1,5e5,7cs

1. In combination, a stretch of railway track, a source of alternating track circuit current connected across the rails of the stretch, a transformer having a primary winding connected across the rails of the stretch, a track relay connected with the secondary of said twnsiormer, an impedance connected across the rails of said stretch, and a source of train governing loop current having one terminal connected with said impedance and the other terminal connected with an intermediate point in said primary winding, the parts being so proportioned that if a track rail breaks so that all or the loop current flows through one section of said primary winding the current induced thereby in the secondary winding will not be of suilicicnt value to operate said track relay.

2. in combination, a stretch of railway track, a source of alternating track circuit current connected across the rails of the strcch, a transformer ha ing a primary winding connected across the rails of the stretch, a track relay connected with the secondary of said tr-ns'l'ornier an impedance connected 211'" the r. of said stretch, and a son -e of train governing loop current having one terminal connected with said impedance andthe other terminal connected with the mid point of said primary windin the parts being so proportioned that if a track rail breaks so that all of the loop current flows through half of said primary winding the current induced thereby in said secondary winding will not be of sinl'icient value to operate said track relay.

3. in combination. a plurality of successsive so tions of railway track. a source of track circuit current for each section connectel across the rails thereof: a transformer for each so; ion having a primary winding con; cted across the rails oi the .ssociated section, a track relay for each ecion connected with the secondary of the vorresponding transformer. an impedance or each section connected across the rails f the associated section, and a separate source of train governing loop current for each section local to suchsection and having one terminal connected with the corresponding impedance and having the remaining terminal connected with an interme diate point in the primary winding of the associated transformer, the parts being so proportioned that if a track rail in a section breaks so that all of the loop current for such section flows through one portion of the primary winding of the associated transformer the current induced thereby in the secondary winding of such transformer will not be of suiiicient value to operate the associated track relay.

4. In combination, a stretch of railway track having electric propulsion current flowing in the rails thereof, means for in sulating a section of track from the remainder of said stretch, impedance bonds for conducting propulsion current past said means, a source of alternating track circuit current connected across the rails of said section, a transformer having a primary winding connected across the rails of said section, a relay connected with the secondary winding of said transformer, and a source of train governing loop current local to said section and having one terminal connected with an intermediate point in said primary winding and the other terminal connected with one of said impedance bonds, the parts being so proportioned that if a track rail breaks so that all of the loop current flows through one section of said primary winding the current induced thereby in the secondary winding will not be of sufficient value to operate said track relay.

5. In combination, a stretch of railway track, a transformer having one winding comprising two portions and connected across the rails of said stretch, means for supplying to said stretch a train controlling current which flows in opposite directions in said two portions at any instant, and a relay connected with a second winding pf said transformer, the parts being so proportioned that if a track rail breaks so that all of the train controlling current flows through one portion of the said one transformer winding, the current induced thereby in the second transformer winding will not be of sufficient value to operate said relay.

6. In combination, a stretch of railway track, a source of track circuit current connected across the rails of the stretch, means for supplying train. controlling current to the rails of the section in parallel, a track relay, and a transformer for supplying track circuit current from said stretch to said relay with one transformation ratio and for supplying train controlling current to said relay from said stretch with a different transformation ratio, the parts being so proportioned that when train controlling current is supplied to the relay by the transformer the value of such current is not sufficient to operate the relay.

7. In combination, a section of railway track, a source of track circuit current connected aross the rails of said stretch, a transformer having a primary winding comprising two portions connected across the rails of said stretch, a loop circuit for said stretch including the two portions of said winding in parallel but oppositely connected, and a track relay connected with the secondary of said transfomrer, the parts being so proportioned that if a track rail breaks so that all of the loop current passes through one portion of the primary winding the current induced thereby in the secondary will not be of sufiicient value to operate the track relay.

8. In combination, a section of railway track, a source of alternating track circuit current connected with the rails of said section, a transformer having its primary connected with the rails of said section, a track relay connected with the secondary of said transformer, an impedance connected across the rails of said section, and a loop transformer local to said section and having one terminal connected with an intermediate point in the primary of said transformer and the other terminal connected with said impedance, the parts being so proportioned that if a track rail breaks so that all of the loop current flows through one section of said primary winding the current induced thereby in the secondary winding will not be of sufficient value to operate said track relay.

In testimony whereof I afliX my signature.

CONRAD I-I. ZIERDT. 

